Laser thermoacoustic modulation for space charge measurement

Abstract

A new method for measuring the space charge distribution in polymer insulators has been developed. This frequency method is based on the thermoacoustic signal which propagates into the insulator when a chopped laser beam is modulated in intensity and focused on the surface of the sample. This method has been used for measuring space charge distribution in a polyethyleneterephtalate sample.

Probing Metastable Space-Charge Potentials in a Wide Band Gap Semiconductor

“…As a route to probing space charge in insulators, our strategy is complementary to scanning-probe methods 9,10 , higher in resolution but restricted to examining surfaces. It also provides an alternative to acoustic-or thermal-stimuli methods [27][28][29][30] in that it is light-diffraction-limited and more naturally adapted to the investigation of small defect ensembles. While the present studies focused on diamond, we anticipate comparable behavior in other wide bandgap materials of technological importance.…”